1. Field of the Invention
The present invention relates to an improvement in a camera adapted to use a film cartridge having a movable light shield door.
2. Related Background Art
Cameras each having a movable light shield door opening/closing device for opening/closing a movable light shield door formed on a film cartridge are disclosed in Japanese Laid-Open Patent Application Nos. 1-191836 and 1-191837. In these prior arts, when a switch for detecting if a cartridge chamber cover is closed detects that the cartridge chamber cover is closed, a movable light shield door is opened, and a film is extracted via the movable light shield door to prevent film exposure. After a predetermined period of time has elapsed from the end of the rewind operation of a film, if the movable light shield door remains open, an alarm is generated. Furthermore, the prior art describes an embodiment which prevents inadvertent exposure of a film by inhibiting the cartridge chamber cover from being opened when the movable light shield door is open.
A movable light shield door is also disclosed in U.S. Pat. No. 4,938,429. In this reference, a light shield door is opened/closed by pivoting a rotatable shaft.
In the above-mentioned prior arts, an operation member for opening/closing the cartridge chamber cover of a camera is locked while the movable light shield door is open. A lock member for locking the operation member is operated integrally with the movable light shield door by the driving force from a motor. In this arrangement, if the movable light shield door cannot be mechanically closed due to some accident (for example, the motor is locked or a film portion is extracted from a cartridge), the lock member cannot be operated even if the lock member can be forcibly externally operated.
Therefore, in the above-mentioned prior art, when the movable light shield door cannot be closed due to some accident, the cartridge chamber cover of the camera can never be opened, and the film cartridge cannot be unloaded.